One-half width circuit breaker mounting means



Nov. 21, 1967 G. w. KNECHT 3,354,284

ONE-HALF WIDTH CIRCUIT BREAKER MOUNTING MEANS Filed March 2, 1966INVENTOR. 660/?66 M /(1/CH 7 M WX ax AW;

A T TORNE United States Patent 3,354,234 ONE-HALF WIDTH CIRCUIT BREAKERI MOUNTING MEANS George W. Kneeht, Brooklyn, N.Y., assignor to MurrayManufacturing Corporation, Brooklyn, N.Y., a corporation of New YorkFiled Mar. 2, 1966, Ser. No. 531,259 4 Claims. (Cl. 200-168) ABSTRACT OFTHE DISCLOSURE A resilient leaf for mounting a circuit breaker 'of thetype used on a mounting panel including a flange having an invertedL-shaped cross section. The leaf extends from one lower corner of thebreaker and has an upstanding sharp edge which may pass under theL-shaped portion when the breaker is angularly inserted, and whichengages the underside when the breaker is seated, thereby preventing itsmovement.

This invention relates to circuit breakers and in particular to anarrangement coacting between the circuit breaker and the panelboard formounting the former on the latter.

The conventional load center, for home and light industrial application,comprises two or more power buses from which bus blades project in aparallel array; the blades of the buses being alternated so thatneighboring blades are associated with opposite polarity buses. Thespacing between adjacent blades is approximately one inch and isdesigned to accommodate the standard oneinch width circuit breaker.

Several years ago, half-inch width circuit breakers made theirappearance on the market, and while panelboards may be constructedspecifically to utilize what will be hereinafter referred to ashalf-width breakers, it is highly desirable to utilize existingpanelboards adapted for standard width breakers.

The conventional circuit breaker, be it single or double pole, isdesigned with a receptive contact clip centered at the lower frontcorner. When applied to a bus blade, the breaker sits astride the bladewith a contact clip gripping its opposite sides and one-half of thebreaker width overhanging the blade on either side. Since a neighboringunit is likewise disposed on a bus blade one inch away, the two unitsare contiguous. The innovation of half-width breakers does notnecessarily double the circuit breaker capacity of a given load centeror panelboard. This arises because of the fact that if the half-widthbreaker sits astride a bus bar blade as did the conventional one-inchbreaker, the additional space saved is not utilized. One arrangement forefiiciently utilizing this space is, however, shown in copendingapplication Ser. No. 405,353, filed October 21, 1964, now Patent No.3,283,110, to the same assignee. With this arrangement, half-Widthbreakers include side-wiping contacts which, by virtue of a specialadapter sitting astride the bus bar stab, may be positioned either tothe left or the right of the circuit breaker. In this manner, twocircuit breakers may be placed between adjacent stabs, each breakermaking electrical contact with the outside stab. It has been found,however, that with conventional means for seating the breaker in thepanelboard, the use of the adapter (described in the patent) may bedefeated by the simple experient of inserting an object into the breakerto force the side-wiping contact to the appropriate side. This, needlessto say, could be quite hazardous.

A further consideration which arises from the substitution of half-widthcircuit breakers in a panelboard designed for use with standard widthbreakers is the means for mounting the breaker end opposite that atwhich the side wiping electrical contact is made in such a manner as topreclude slippage of the breaker either laterally or longitudinally.

Accordingly, it is the object of this invention to provide anarrangement for mounting circuit breakers in a panelboard or load centerto preclude slippage of the breaker either longitudinally or laterally.

It is a further object of this invention to provide a circuit breakermounting means which coacts with the panelboard to preclude theinsertion of foreign objects in an attempt to defeat the necessity forthe prescribed elements.

It is a still further object of this invention to provide visual meansfor indicating that such an unauthorized attempt has been made.

The above mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will best be understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theacompanying drawings wherein:

FIG. 1 is a perspective illustration of a standard halfwidth circuitbreaker according to the invention in conjunction with the panelboardmounting means for accommodating these breakers;

FIG. 2 illustrates the use of the inventive breaker with differentpanelboard mounting means;

FIGS. 31a and 3b are plan and partial elevation views, respectively, ofconventional and half-width breakers in mounted position upon apanelboard;

FIGS. 4a and 4b are sectional views of the inventive mounting meansduring the initial and final seating of the breaker respectively.

Turning now to the figures and in particular to FIG. 1, there may beseen the conventional standard width breaker A, the foot end of which isshown ready to mount on the panelboard mounting means 10. The bus barstabs 12, 13 and 14 are alternately associated with dilferent polaritybuses as previously mentioned; for simplicity, only the tops of thestabs are shown. With the conventional arrangement, the front end ofbreaker A (not shown) sits astride bus bar stab 12 after the foot endhas been located as will be described. To position the foot end ofconventional breaker A, the breaker cavity 16 is positioned over theinverted L-shaped flange 17; the breaker being angularly rotated to sitastride the blade 12. Lateral displacement of the breaker is precludedby the side of cavity 16 abutting upon the sides of the flange 17.

The breaker of the type to which the invention is directed is depictedas B in FIG. 1. As may be seen, the front end of this breaker includes aside wiping contact 11 which emerges through a window 15 to bear againstthe rear side of bus bar stab 14. The relative position of the front endof this breaker, as well as the means for affording sufficient sidewiping contact pressure, is provided by an adapter (described in patentapplication Ser. No. 405,353, filed Oct. 21, 1964). Since the inventiondoes not depend upon the precise manner in which the front end of thebreaker is retained in sidewiping position, for the sake of brevity, theadapter has been omitted from this application. Sullice to say, however,that some means are afforded for retaining the front end of the breakerin position with stab 14 and contact 11 in wiping engagement and anexemplary means may be seen by reference to the above patentapplication.

The modification of the breaker according to the invention may be seenin the lower front corner and essentially comprises the adjunct 20, aportion of which is shown in this figure. Before analyzing this elementin detail, its function relative to the conventional panelboard mountingmeans, as well as to the modified panelboard mounting means shown inFIG. 2 will be discussed. Ele- 9 o) ment 2b, as may be seen, is forked,the separate branches being resilient perpendicular to the plane oftheir faces.

When this element is inserted under the flange 19, and the breaker isangularly displaced in a manner similar to that of breaker A explainedabove (to seat the side wiping contact end), a portion a of element 20resiliently contacts one portion of the flange 19, retaining it inposition in a manner to be described.

FIG. 2 shows an alternative panelboard arrangement which may also beutilized with the invention. As may be seen by comparison between therespective panelboard foot mounts 17, 18 and 19 in FIG. 1 and 23 in FIG.2, the latter mounts are continuous and it is not required that they beindividually lanced, such as shown in FIG. 1 in order to function. This,needless to say, arises as a consequence of the fact that whereas theconventional arrangement utilizes cavities, the invention employs anelement which extends out of the breaker and therefore does not requiremating means to enter a cavity. It is preferable with the arrangementshown in FIG. 2 that the areas where the foot end of the breaker is tobe located be marked (such as in the black and white fashion shown) sothat visual location of the foot end of the breaker may beachieved.

FIGS. 4a and 4b illustrate the manner in which the lower end of thebreaker is located With respect to the panelboard. In FIG. 4a thebreaker is shown with one fork 20a of leaf 20 being inserted under theinverted L-shaped flange 19. As may be seen in this figure, no contactoccurs at this point between the leaf and the panelboard flange. As alsomay be seen from this figure, leaf 20 is C-shaped with the portion 20entering the cavity 27 within the breaker to add resilience and retainthe leaf in position. When the breaker is angularly displaced about thefulcrum as shown in FIG. 4b, the perpendicular serration on portion 20ais brought to bear against the underside of the flange 19. Preferably,the leaf is made of a rather hard metal so that the serrated points(better seen in FIG. 1) may slightly penetrate the underside of theflange, retaining the foot end of the breaker in position. Because ofthis contact force, if the front end of the breaker is not retained inposition by means-of the adapter previously mentioned (not shown) butrather some implement is utilized to circumvent the use of the adapter,the torque force upon the circuit breaker via the resiliency of the leaf20 and fulcrum 25 will cause the front end to rise; i.e. in FIG. 4b thebreaker will rotate counterclockwise. Thus, a visual indication will begiven the user that the method he has chosen to mount the breaker is anincorrect one and hazardous.

FIGS. 3a and 3b show top and end views of one conventional and threehalf width circuit breakers mounted upon a panelboard. The conventionalbreaker is shown as in normal use sitting astride the bus blade 12 withthe flange 17 disposed in the breaker cavity. The breakers 13 and C arejuxtaposed half-width breakers, each sitting on either side of bus stab13, the internal front portions of the breakers including facingcontacts 11 and 11' for the corresponding opposite blade faces. As maybe seen most clearly in the partial end view, one branch of each of themounting elements 20 and 20 is flexed beneath the underside of theinverted L-shaped flange 18.

Half-width breaker D is shown in FIGS. 3a and 3b to illustrate analternative arrangement for locating the foot end of the half-widthbreakers with respect to the panel mounts. In this case, the breaker isprovided with a pair of abutting surfaces 21 and 22 for engaging one ofthe correspondingly denoted (and primed) panelboard flange abutments 2iand 22 on flange 19. The foregoing results in a physical rather than avisual (as shown in FIG. 2) positioning of the foot end of the breaker.

While the principles of the invention have been described in connectionwith specific apparatus, it is to be clearly understood that thisdescription is made only by way of example and not as a limitation tothe scope of the invention as set forth in the objects thereof and inthe accompanying claims.

What is claimed is:

1. In a circuit breaker of the type used with a mounting panel,including a flange having an inverted L-shaped cross-section, theimprovement therein comprising: a resilient leaf extending from one endof the breaker for entering the inverted L-shaped portion of saidmounting panel without substantial contact; and a sharp relatively hardedge upstanding from the external edge of said leaf, said edge normallycontacting the underside of said L- shaped mounting panel member whensaid breaker is seated, whereby said breaker must be angled for entry ofsaid leaf under said inverted L-shaped mounting panel member and thenangularly displaced to the normal seated position whereupon the edge ofsaid leaf engages the underside of said member, preventing lateral orlongi tudinal movement of said breaker.

2. The improvement claimed in claim 1 wherein said leaf i forked andincludes two upstanding edges.

3. The improvement claimed in claim 2 wherein said breaker and mountingpanel include cooperating means for physically locating the end of saidbreaker at which the leaf is located.

4. The improvement claimed in claim 1 wherein said leaf is of C-shapedcross-section and is retained within an L-shaped cavity in said breaker.

References Cited 7 UNITED STATES PATENTS 3,172,014 3/1965 Johnson .3l7-1l9 3,289,049 11/1966 Middendorf 200168 ROBERT K. SCHAEFER, PrimaryExaminer. H. O. JONES, Assistant Examiner.

1. IN A CIRCUIT BREAKER OF THE TYPE USED WITH A MOUNTING PANEL,INCLUDING A FLANGE HAVING AN INVERTED L-SHAPED CROSS-SECTION, THEIMPROVEMENT THEREIN COMPRISING: A RESILIENT LEAF EXTENDING FROM ONE ENDOF THE BREAKER FOR ENTERING THE INVERTED L-SHAPED PORTION OF SAIDMOUNTING PANEL WITHOUT SUBSTANTIAL CONTACT; AND A SHARP RELATIVELY HARDEGE UPSTANDING FROM THE EXTERNAL EDGE OF SAID LEAF, SAID EDGE NORMALLYCONTACTING THE UNDER SIDE OF SAID LSHAPED MOUNTING PANEL MEMBER WHENSAID BREAKER IS SEATED, WHEREBY SAID BREAKER MUST BE ANGLED FOR ENTRY OFSAID LEAF UNDER SAID INVERTED L-SHAPED MOUNTING PANEL MEMBER AND THENANGULARLY DISPLACED TO THE NORMAL SEATED POSITION WHEREUPON THE EDGE OFSAID LEAF ENGAGES THE UNDERSIDE OF SAID MEMBER, PREVENTING LATERAL ORLONGITUDINAL MOVEMENT OF SAID BREAKER.